412 H. A. Newton— Biela Meteors of Nov. 21th, 1885. 



At Glasgow one observer counted 74 in a minute at 6 h 10 m , 

 and another counted 100 in a minute at 6 h 24 m . 



At Greenwich there were 30 to 40 a minute for one observer 

 between 6 h and 7 h . 



From Bey rout, Professor Robert H. West of the Syrian Prot- 

 estant College reports in Nature (vol. xxxiii, p. 152) : " The 

 maximum appears to have been between 8 and 9 o'clock. At 

 6 h 3 m two observers watching opposite parts of the sky counted 

 850 meteors in five minutes. At 7 h 50 m (5 h 30 m Greenwich 

 mean time) seven observers divided the heavens among them 

 and together counted 525 in one minute. We all agreed that 

 we had not been able to count all that we saw, so that this num- 

 ber is probably too small. At any rate I do not think the 

 number of meteors visible between 7 and 9 P. M. was at any 

 time less than 500 per minute. At 10 h I alone counted 210 in 

 two minutes, facing the north, which was then partially clouded." 



The number 525 for seven observers corresponds to 525 X 

 325-^1282=133 per minute for one observer, and to a total 

 hourly number (computed as before) of 59,000. The count of 

 850 in 5 m for two observers represents 87 per minute for one 

 observer. 



At Moncalieri the 6200 for 4 observers in a quarter hour in 

 like manner represents about 60,000 per hour for the total num- 

 ber visible. 



In many other places larger or smaller numbers were reported. 

 Over 100 in individual minutes were counted by a single 

 observer in several places. It ean hardly be doubted that there 

 was a purer sky and so a larger number of meteors visible at 

 Beyrout, Moncalieri and Marseilles than at Upsala and Green- 

 wich.* In computing the hourly number of meteors visible 

 we should choose the clearer rather than the hazy skies. Prob- 

 ably it will not be considered unreasonable to assume from these 

 observations, that the density of the meteor stream in its cen- 

 tral and densest portions may be fairly expressed by 75,000 

 meteors per hour visible at one place in a very pure clear sky 

 by a very great number of observers. 



By an extended examination of meteor paths it was shown in 

 1864 (this Journal, II, xxxix, p. 196) that about one in fifty (one 

 in 50*35) of all shooting stars visible at a place should have the 

 middle points of their apparent paths within 10° of the zenith. 

 The hourly number of meteors within 10° of the zenith at the 

 time of the maximum, Nov. 27th, was then 75,000/50, or 

 1500. 



* It is not reasonable to suppose that the product of the number of meteoroids 

 that entered the air near the several places multiplied by the cosine of the zenith 

 distant of the radiant greatly differed. Can a different constitution of the upper 

 strata of the atmosphere, by reason of which paths become more brilliant in 

 one place than in another be admitted as possible ? 



